Fig. 1

a Strict component consensus of 41 most parsimonious trees of length 3739. Numbers in italic are bootstrap values. A bootstrap analysis with 5,000 replicates was carried out. Only values greater than 50% are shown. Numbers in bold are decay indices. A decay index PAUP file was written in MacClade (Maddison and Maddison 2003) and implemented in PAUP 4.10b (Swofford 2002). The cladistic analysis was carried out using the gap weighting methodology (see Maidment et al. 2008 for details), which involves weighting all characters to a value of 26. Decay indices are therefore 26 times greater than would be expected in a normally weighted analysis. A decay index of 26 in this analysis is equivalent to a decay index of 1 in a normally weighted analysis; all decay indices lower than 26 indicate the clade is supported by continuous data only. b Strict reduced consensus tree 3 (CIC = 55.83 bits) in which two unstable taxa, Jiangjunosaurus and Gigantspinosaurus, have been pruned, resulting in improved resolution. Numbers above clades indicate named clades as follows: 1 Thyreophoroidea, 2 Eurypoda, 3 Ankylosauria, 4 Stegosauria, 5 Huayangosauridae, 6 Stegosauridae, 7 Dacentrurinae, 8Stegosaurus